Metal-oxide thin films are used in a wide variety of electronic devices. Although many techniques have been developed to deposit thin films of metal oxides, there is still a need for alternative cost- and energy-effective deposition methods. Deposition of metal oxide thin films from aqueous solutions of all-inorganic metal salts is a viable method that meets these needs. Although many aqueous-deposited metal-oxide thin films have been successfully incorporated into functioning devices, many of the mechanisms that occur as precursors transition to metal oxides are not well understood. The work presented in this dissertation is primarily concerned with examining the processes that occur as metal oxide thin films form from spin-deposited aqueous precursor solutions with a particular focus on the role of H2O in these processes. Chapter I summarizes methods for thin film deposition, and describes the use of aqueous metal salt solutions as viable precursors for the deposition of metal oxide thin films. Chapter II investigates the precursor chemistry, film-formation processes and properties of LaAlO3 thin films deposited from aqueous precursors. This chapter also serves as general guide to the processes that occur as metal-oxide thin films form from spin-deposited aqueous precursors. Chapters III and IV focus on the effects of H2O(g) during spin-deposition of precursor thin films and during the annealing process in which precursors are converted to metal oxides, respectively. The presence of H2O(g) during spin-deposition has a striking effect on the thickness of the resulting thin films and also affects the elemental gradient and density profiles. During annealing, H2O(g) reduces the temperatures at which counterions are expelled and influences the metal-hydroxide framework formation and its condensation to a metal oxide. The data also indicate that H2O(g) enhances diffusion of gaseous byproducts from within the films. Chapter V focuses on precursor concentration and its impact on the thermal evolution of thin films. The processes involved in the conversion of precursors to metal oxide thin films occur at lower temperatures as precursor concentration decreases. Although this is likely in part due to thickness effects, concentration-dependent precursor speciation may also be involved in lowering the temperatures at which films densify. / 2019-02-17

Lee Wai Tak Joseph = Fe₃₋xZnxO₄的真空熱處理效應及磁隧道結 / 李懷德. / On t.p. "-x" and "x" is subscript. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Lee Wai Tak Joseph = Fe₃₋xZnxO₄ de zhen kong re chu li xiao ying ji ci sui dao jie / Li Huaide. / Acknowledgement --- p.i / Abstract --- p.ii / 論文摘要 --- p.iii / Table of contents --- p.iv / List of Figures --- p.ix / List of Tables --- p.xiv / Table of Contents / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Introduction to Magnetite Fe3O4 and Zinc Ferrite Fe3.-xZnxO4 --- p.1-1 / Chapter 1.1.1 --- Crystal structure and Properties of Fe304 and Fe3-xZnxo4 --- p.1-1 / Chapter 1.1.2 --- Transformation of Iron Oxides --- p.1-6 / Chapter 1.2 --- Verwey transition --- p.1-10 / Chapter 1.2.1 --- Introduction --- p.1-10 / Chapter 1.2.2 --- Charge-orbital ordering --- p.1-15 / Chapter 1.3 --- Trilayer Magnetic Tunneling Junction (MTJ) --- p.1-18 / Chapter 1.3.1 --- Half-metallic Fe3O4 --- p.1-18 / Chapter 1.3.2 --- Tunneling Magnetoresistance (TMR) --- p.1-19 / Chapter 1.4 --- Research Motivation --- p.1-20 / Chapter 1.5 --- Scope of this thesis --- p.1-21 / References --- p.1-22 / Chapter Chapter 2 --- Instrumentation / Chapter 2.1 --- Sample Preparation --- p.2-1 / Chapter 2.1.1 --- Vacuum System --- p.2-1 / Chapter 2.1.2 --- Facing-target Sputtering (FTS) Technique --- p.2-3 / Chapter 2.2 --- Sample Treatment --- p.2-7 / Chapter 2.2.1 --- Vacuum Annealing (VA) --- p.2-7 / Chapter 2.2.2 --- Silver Electrode Coating System --- p.2-9 / Chapter 2.3 --- Sample Characterization --- p.2-11 / Chapter 2.3.1 --- Four-point-probe DC Resistivity Measurement --- p.2-11 / Chapter 2.3.2 --- Current-Voltage Measurement (IV) --- p.2-11 / Chapter 2.3.3. --- X-ray Diffraction (XRD) --- p.2-13 / Chapter 2.3.4 --- X-ray Fluorescence (XRF) Method --- p.2-14 / Chapter 2.3.5 --- Alpha-step Surface Profiler --- p.2-14 / Chapter 2.3.6 --- Atomic Force Microscope (AFM) --- p.2-15 / References --- p.2-16 / Chapter Chapter 3 --- Fabrication of Fe3- xZnxO4Thin Films / Chapter 3.1 --- Thin Film Deposition --- p.3-1 / Chapter 3.1.1 --- Review of Deposition Procedures --- p.3-1 / Chapter 3.1.2 --- Preparation of Substrates --- p.3-6 / Chapter 3.1.3 --- Deposition of Fe3-xZnxO4 thin films --- p.3-7 / Chapter 3.2 --- Characterization of Fe3-xZnxO4 thin films --- p.3-9 / Chapter 3.2.1 --- Surface Morphology --- p.3-9 / Chapter 3.2.2 --- Temperature-Dependent Resistivity Measurement --- p.3-11 / Chapter 3.3 --- Factors affecting the Quality of films --- p.3-18 / Chapter 3.3.1 --- Effect of Substrates --- p.3-18 / Chapter 3.3.2 --- Effects of Sputtering Power --- p.3-21 / Chapter 3.3.3 --- Effects of Temperature --- p.3-24 / Chapter 3.3.4 --- Effects of Thickness --- p.3-29 / Chapter 3.4 --- Chapter summary --- p.3-32 / References --- p.3-33 / Chapter Chapter 4 --- Vacuum Annealing of Fe3-xZnxO4 Thin Films / Chapter 4.1 --- Introduction --- p.4-1 / Chapter 4.2 --- Post-Annealing Effect in the Presence of Oxygen --- p.4-6 / Chapter 4.3 --- Vacuum Annealing of Fe3-xZnx04 thin films --- p.4-12 / Chapter 4.3.1 --- First Stage of Vacuum Annealing --- p.4-12 / Chapter 4.3.2 --- Second Stage of Vacuum Annealing --- p.4-17 / Chapter 4.3.3 --- Third Stage of Vacuum Annealing --- p.4-25 / Chapter 4.4 --- Chapter summary --- p.4-32 / References --- p.4-33 / Chapter Chapter 5 --- Trilayer Magnetic Tunneling Junction (MTJ) / Chapter 5.1 --- Introduction --- p.5-1 / Chapter 5.2 --- Fabrication of Trilayer Magnetic Tunneling Junction --- p.5-3 / Chapter 5.3 --- Tunneling Magnetoresistance (TMR) --- p.5-5 / Chapter 5.3.1 --- Current-Voltage Characteristic Curve (IV curve) --- p.5-5 / Chapter 5.3.2 --- Magnetoresistance Measurement --- p.5-8 / References --- p.5-10 / Chapter Chapter 6 --- Conclusions / Chapter 6.1 --- Conclusions --- p.6-1 / Chapter 6.2 --- Further research --- p.6-2 / References --- p.6-3

銅銦鎵硒薄膜太陽能電池因為其高效率及相對低廉的成本，商業應用已經開始陸續出現。我們自主研發的集成式銅銦鎵硒薄膜電池生產系統可以全程製作襯底大小為10cm x 10cm 的電池及剃型組件。本研究工作主要分為兩個方向:第一個方向是研究及測試生長高效率太陽能電池及組件的具體條件。通過儀器改進及電池每層鍍膜的條件優化，能夠重複的生長高效率電池及組件; 第二個方向是通過減少銅銦鎵硒吸光習的厚度從而達到降低電池生產成本的目的。 / 銅銦鎵硒採用三步共蒸法製備吸收層。第一步先蒸發銦、鎵、硒三種元素形成n型硒化銦(鎵)薄膜;第二步蒸發銅、硒形成銦鎵硒半導體薄膜; 第三步蒸發一層額外的型硒化銦(鎵)薄膜保證整體電池是p型半導體。三步期間的襯底溫度經過小心調試，以使得合適的鎵梯度能夠在吸收層裹形成。通過每一層的條件優化我們能夠生長出高光電轉換效率的太陽能電池(17%)及組件(12%)。 / 太陽能電池的變溫測試及弱光測試對瞭解其應用潛能存在非常重要的作用。通過多組對比實驗發現銅銦鎵硒電池的溫度係數可以通過增加鎵在吸收層的組分而得到改善。同時，電池的弱光表現可以通過減少銅的量得到很大的提高。STM 的研究發現弱光表現得到改善是因為吸收層顆粒介面電阻的增加而導致的。 / 減少吸收層的厚度有利於進一步減少太陽能電池的材料成本。當電池的吸收層厚度小於一微米時，開路電壓跟短路電流都明顯有所減少，從而導致太陽能電池效率降低。更薄電池效率的提高可以從兩個方面來實現:氧化鋅表面的陷光結構及更加合適的鎵含量的使用。通過這兩艇改進方法，電池效率被提高到14%以上，使得超薄電池有更好的應用前景。 / Cu(In,Ga)Se₂ (CIGS)-based thin film solar cell has been commercialized recently due to its high energy conversion efficiency. We have designed an integrated satellite deposition system for producing CIGS solar cell with substrate size of 10cm x 10cm. This work mainly contains two parts with first part focusing on growing and characterizing high quality baseline solar cells and solar modules and second part concentrating on further reducing the material costs by growing thinner absorber layer with high efficiency. / The most difficult part in growing high quality CIGS solar cells originate from the absorber layers which contain p-type chalcopyrite structures with four different elements: Cu, In, Ga and Se. The widely used three-stage process is employed to co-evaporate In, Ga and Se first, then Cu and Se are evaporated to form the chalcopyrite CIGS structure and additional In, Ga and Se are deposited in the end to ensure an overall Cu deficiency, which is important for getting p-type semiconductors. The substrate temperatures during these three stages are carefully adjusted to introduce proper gallium gradients which is important for collecting electrons efficiently. Together with optimizing other layers we are able to get cell efficiency (area around 0.5 cm²) over 17%. To produce CIGS mini-modules, laser scribing as well as mechanical scribing are employed for series interconnection of individual cells using monolithic integration. The power and speed of laser together with the condition of mechanical scriber are carefully adjusted to ensure a minimum dead area in the module. Module (area around 80 cm²) with efficiency over 12% is produced. / Solar cells were fabricated and tested under varied temperature and weak light conditions. Temperature coefficient is compared between CIGS solar cells and other types of solar cells. Temperature coefficient is improved a lot with higher gallium content in the absorber layer. Weak light performance is shown to be increased a lot when copper percentage is lowered down. In order to examine the origin of beneficial effects from Cu-poor absorber, solar cells are grown with comparable grain sizes using our technique and I-V performances are examined under STM in grain/atomic scale. Leakage current is found to be mainly originates from boundary area. CIGS solar cells with Cu-poor absorber benefit from the reduced leakage from boundary area. / CIGS solar cells with thinner absorber thickness are studied and compared with conventional CIGS solar cells. We have found that high conversion efficiency solar cells can be grown for absorber thickness as thin as 1.5μm. Further reduction in absorber thickness deteriorates solar cell performances in both V∝ and Jsc resulting in conversion efficiency as low as 11%. / Two major approaches are performed to improve solar cell performances. Light trapping by etching AZO top contact for creating pyramid-structures to enhance light scattering. Efficiency is increased by more than 1.5% for solar cells with etched AZO surfaces. Solar cells with efficiency larger than 13% can be grown by using AZO etching. Another approach is by using suitable Ga content in absorber layer. Solar cells with efficiency as high as 14.17% are grown which makes thinner CIGS solar cells very competitive. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Yang, Shihang = 高效率、低成本銅銦鎵硒薄膜太陽能電池的製造 / 楊世航. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 101-109). / Abstract also in Chinese. / Yang, Shihang = Gao xiao lu, di cheng ben tong yin jia xi bo mo tai yang neng dian chi de zhi zao / Yang Shihang. / Chapter 1 --- Introduction to Photovoltaics --- p.1 / Chapter 1.1 --- Energy crisis --- p.1 / Chapter 1.2 --- Physics of solar cells --- p.4 / Chapter 1.2.1 --- Light Absorption --- p.4 / Chapter 1.2.2 --- Charge Carrier Separation --- p.8 / Chapter 1.2.3 --- Solar Cell I-V Characteristics --- p.9 / Chapter 1.3 --- Classifications of Solar Cells --- p.11 / Chapter 1.3.1 --- Crystalline silicon solar cell --- p.11 / Chapter 1.3.2 --- Thin film solar cells --- p.12 / Chapter 1.3.3 --- Organic and polymer solar cells --- p.13 / Chapter 1.4 --- Cu(In,Ga)Se₂ (CIGS) based Solar Cells --- p.13 / Chapter 1.4.1 --- State of the art --- p.13 / Chapter 1.4.2 --- Material properties and structures --- p.14 / Chapter 1.4.3 --- CIGS advantages --- p.17 / Chapter 2 --- Integrated CIGS deposition system and fabrication process optimization --- p.21 / Chapter 2.1 --- Introduction to vacuum deposition system --- p.21 / Chapter 2.1.1 --- Integrated CIGS solar cell deposition system --- p.21 / Chapter 2.1.2 --- Ni-Al top grid evaporation system --- p.23 / Chapter 2.2 --- Fabrication processes --- p.23 / Chapter 2.2.1 --- Substrate treatment --- p.23 / Chapter 2.2.2 --- Molybdenum back contact deposition --- p.24 / Chapter 2.2.3 --- CIGS absorber layer formation --- p.26 / Chapter 2.2.4 --- Hetero-junction formation --- p.31 / Chapter 2.2.5 --- Window layer optimization --- p.32 / Chapter 2.2.6 --- Laser and mechanical scribing for mini-modules fabrication --- p.37 / Chapter 2.3 --- Equipment improvements --- p.42 / Chapter 2.3.1 --- Heating uniformity of substrate --- p.42 / Chapter 2.3.2 --- Use of pyrometer for improved control of absorber thickness/composition --- p.43 / Chapter 2.3.3 --- Se cracking unit --- p.45 / Chapter 2.4 --- Characterization of CIGS solar cells --- p.47 / Chapter 2.4.1 --- Morphology, composition and crystallinity --- p.47 / Chapter 2.4.2 --- Depth profile of CIGS --- p.49 / Chapter 2.4.3 --- Electrical property measurements --- p.51 / Chapter 2.5 --- Conclusion --- p.54 / Chapter 3 --- Performance of CIGS solar cells under non-standard test conditions --- p.56 / Chapter 3.1 --- Temperature coefficient measurement of CIGS --- p.57 / Chapter 3.1.1 --- Equipment set-up --- p.57 / Chapter 3.1.2 --- Temperature coefficients for different types of solar cells . --- p.60 / Chapter 3.1.3 --- CIGS solar cells with varied Ga/III composition --- p.65 / Chapter 3.2 --- Weak Light Performance of CIGS --- p.69 / Chapter 3.2.1 --- Introduction --- p.69 / Chapter 3.2.2 --- Experiment --- p.72 / Chapter 3.2.3 --- Results and discussion --- p.73 / Chapter 3.3 --- Conclusion --- p.81 / Chapter 4 --- CIGS solar cells with lower fabrication cost --- p.83 / Chapter 4.1 --- Fabrication cost analysis for commercial CIGS solar cells --- p.83 / Chapter 4.2 --- Thinner CIGS absorber layer --- p.84 / Chapter 4.2.1 --- Solar cell performances with different absorber thicknesses --- p.84 / Chapter 4.2.2 --- Performance improvement for thinner solar cell --- p.87 / Chapter 4.3 --- Conclusion --- p.96 / Chapter 5 --- Conclusion --- p.98 / Chapter 5.1 --- Summary of previous researches --- p.98 / Chapter 5.2 --- Future work --- p.99 / Bibliography --- p.101

There is a considerable interest in the use of tungsten oxide in the research and development of new materials and devices, such as gas sensors and as photocatalysts. In order to improve the photocatalytic properties of WO3, its combination with metals which allows the preparation of WMxOy materials are believed to be promising photocatalysts under visible light. The present work deals with the synthesis of homo- and hetero-metallic tungsten alkoxide and amide compounds using the single source precursor approach for potential chemical vapour deposition precursors of mixed-metal oxide films.

There are a number of “smart” coatings that can be applied to glass. These include self-cleaning coatings based on titanium dioxide, and low-E coatings based on fluorine-doped tin oxide. Products are often more desirable with colour options such as Pilkington Activ BlueTM. There are currently no alternatives to body tinting glass to achieve colour, which is a time-consuming and expensive procedure. The work in this project details a number of coloured coatings via the AACVD or combustion processing of metal nitrate/urea precursors.

This thesis focuses on the synthesis and characterisation of titanium dioxide (TiO2) thin films for photocatalytic applications and use in semi-transparent dye-sensitised solar cells for energy efficient glazing. Several synthetic methods for the production of TiO2 thin films are explored including sol-gel, aerosol-assisted chemical vapour deposition (CVD) and hybrid combinatorial CVD. For sol-gel processing two different precursors were studied; titanium tetra-isopropoxide (TTIP) and titanium bis-ammonium lactato dihydroxide (TiBALD). Non-ionic surfactants (Tween 20, 40, 60 and Brij 58 and 98) were successfully incorporated into all three methods for the production of TiO2 thin films modified morphology, microstructure and enhanced functional properties in some cases. All films are fully characterised using scanning electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, UV-Vis spectroscopy, contact angle analysis, as well as assessment for photocatalytic performance with resazurin 'intelligent' ink. Photocatalytic performance has been used as an indicator for performance in dye-sensitised solar cells (DSSCs). The best photocatalytic performances with half-lives of up to 2 minutes were obtained for thin films produced with the addition of Brij surfactants. A selection of thin films were tested in semi-transparent DSSC devices with up to 70% transparency, to determine their overall potential for use as energy-efficient glazing. Three DSSC device configurations were tested, whereby the optimum configuration used N3 "black" dye with a dye loading time of 42 hours in combination with a high performance iodine electrolyte and a platinum counter electrode. The highest power conversion efficiencies (PCE) obtained were within the region of 0.1 - 0.3 %, with the highest PCE of 0.3814 % obtained with a 3-layer TTIP sol-gel derived Brij 58 thin film (0.0006 mol dm3) which exhibited an short-circuit current of 0.857 mA/cm2, an open-circuit voltage of 0.71 V and a fill factor of 0.60.

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Physics. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Includes bibliographical references. / by William J. Gallagher. / Ph.D.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Includes bibliographical references. / by James Allen Gregory. / Sc.D.

Neste trabalho são apresentados o projeto, construção, caraterização e utilização de um dispositivo de produção de plasmas por absorção de ondas eletromagnéticas, na frequência ciclotrônica dos elétrons - ECR (\"electron-cyclotron resonance\"), Os fundamentos teóricos dos processos físicos relevantes, tanto com relação a absorção das ondas eletromagnéticas como quanto ao diagnóstico do plasma, são discutidos de forma a permitir uma apresentação completa do tema, A construção e a utilização do dispositivo, para crescimento de filmes semicondutores de interesse sobre substratos de silício, são descritos em detalhe. No caso de filmes de nitreto de boro cúbico, as experiências não tiveram êxito devido a impossibilidade de conseguir a fonte de boro prevista no projeto, decaborana, Já no caso de nitreto de alumínio hexagonal, foi possível demonstrar, pela primeira vez diretamente em dispositivos ECR, o crescimento de grãos policristalinos, A configuração magnética e os parâmetros de plasma apropriados para crescimento de nitreto de alumínio foram devidamente determinados. / The design, construction, and characterization of an electron-cyclotron-resonance (ECR) plasma device, as well as its utilization for deposition of thin semiconductor films, is described in detail. The basic theory of the relevant physical process, regarding electromagnetic wave absorption by the plasma and diagnostic, is discussed in order to provide a self-contained presentation of the subject. The growth of cubic boron nitrite and hexagonal aluminium nitrite over silicon substrates was pursued. In the first case, the experimental procedure was hindered by the impossibility to import decaborane, which was envisaged in the original project as the source of boron. The attempts to other sources were unsuccessful. In the latter case, a successful growth of polycristalins aluminium nitride was achieved, for the first time directly in a ECR plasma), to the best of our knowledge. The magnetic configuration and plasma parameters required for successful crystal growth were determined.

Highly efficient LEDs and photovoltaic cells based on spin coated films of layered Ruddlesden-Popper hybrid perovskites (RPP) have been recently reported. The electronic structure and phase composition of these films remains an open question, with diverse explanations offered accounting for the excellent device performance. Here we report x-ray and optical characterization of hot cast RPP thin films, emphasizing the distribution of structural and electronic properties through the film depth. Our results indicate an at least 70% phase pure n=3 film results from casting a stoichiometric solution of precursors, with minor contributions from n=2 and n=4 phases. We observe a strong correspondence between the predicted single-crystal RPP reciprocal lattice and measured RPP film wide angle scattering pattern, indicating a highly ordered [101] oriented film. This correspondence is broken at the air-film interface where new scattering peaks indicate the existence of a long wavelength structural distortion localized near the films surface. Using transient absorption spectroscopy, we show that the previously detected luminescent mid-gap states are localized on the films surface. Investigating films of varying thickness, we determine the photo-excited carrier dynamics are dominated by diffusion to this interface state, and extract an excitonic diffusivity of 0.18cm2s-1. We suggest that the observed surface distortion is responsible for the creation of luminescent mid-gap states.